Frozen confections are particularly appreciated for their creamy and smooth characteristics. In order preserve the optimum organoleptic characteristics of smoothness, however, the frozen confections need to be stored and handled with care as even small temperature variations can be observed during storage, distribution, or handling. This is particularly the case when a consumer purchases a frozen confectionery and does not consume it quickly. When there is a gap between the time the frozen product is taken from the deep frozen section and placed in a domestic freezer, a partial thawing of the frozen product occurs before it is refrozen. Such cycles of temperature variation, which is known as “heat shock” cause the formation and growth of ice crystals in the product. The formation and growth of ice crystals in the product cause an undesirable crystallized texture in the frozen confectionery. The crystallized texture and the icy mouth feel, as well as the impaired appearance, reduces the overall quality of the frozen confection as perceived by the consumer.
Various gums and emulsifiers have been used as additives to the frozen confection with the aim of improving the stability, smoothness, and the heat shock resistance of aerated frozen confections. For example, U.S. Pat. No. 4,500,553 to Liggett discloses that a gum stabilizer in combination with a monosaccharide and disaccharide sweeteners contributes to limiting the growth of ice crystals upon freezing and storage of frozen confection. In addition, U.S. Pat. No. 4,542,035 to Huang discloses that adding to the product an edible multivalent cationic electrolyte such as calcium, magnesium, aluminum, iron, manganese and the like improve stability of the frozen product.
Traditionally, molded aerated frozen bars, ice cream, or water ice are manufactured by partially freezing an ice cream mix, ice milk mix, frozen yogurt mix, water ice mix, or fruit juice mix in conventional batch or continuous freezers followed by pumping and filling the mix into molds of different shapes and sizes. During the last decade, a new generation of freezers has been developed which are equipped with pre-whippers that enable the mix to be pre-aerated before being partially frozen in the freezer. The molded products are usually quiescently frozen using a cold brine system at −30° C. to −40° C. If desired, after demolding, the molded products may be coated with chocolate or compound coating. Finally, the products are usually packaged and stored at about −30° C. until transport and distribution.
This traditional process for manufacturing molded aerated frozen bars, ice milk, yogurt, ice cream, or water ice is not without limitations. One such limitation, for example, is the formation of an icy texture due to the partial freezing of the mix in the freezer, followed by quiescent freezing in the molds. This also is known to lead to loss of air, and the formation of large air cells in the product having a size range of about 110-185 microns. Arbuckle, W. S. Ice Cream, Fourth Edition, 1986, Van Nostrand Reinhold, New York, p 234.
In addition, shrinkage of the product is often a problem, and when eating the product, a very cold feeling in the mouth is experienced. Furthermore, it is difficult to achieve more than 20% overrun in water ice, a typical overrun is from 0% to 20% and usually is about 5%. Also, it is difficult to achieve more than 80% overrun and quite difficult to achieve an overrun of 120% or higher in finished ice cream products using conventional manufacturing.
Non-molded products have similar problems. Air cells and ice crystals start growing immediately after production of non-molded products. Significant air cell and ice crystal growth occurs during transportation, storage at the grocery store or during transportation and storage of the products by the consumer. There is a need for inhibiting or delaying air cell or ice crystal growth after production or during hardening, transportation, or distribution.
Currently, there is no method that satisfactorily regulates the formation and growth of ice crystals in an aerated frozen confection and no process that can produce very stable finely aerated frozen ice cream, ice milk, yogurt, or water ice having an average air cell size of less than 50 microns and an average ice crystal size of 25 microns or that are heat shock resistant for a period of time after production. Thus, there is a need for finely aerated ice cream, ice milk, yogurt or water ice that maintain a smooth texture, do not suffer from growth of ice crystals, shrinkage, do not give a very cold feeling in the mouth, have an uniform appearance without large air pockets on the surface and have a significantly higher heat shock resistance. The present invention provides products and processes which overcome these disadvantages.